921

Author: ProHiryu

code/921.minimum-add-to-make-parentheses-valid.py

@@ -0,0 +1,18 @@
+#
+# @lc app=leetcode id=921 lang=python3
+#
+# [921] Minimum Add to Make Parentheses Valid
+#
+
+# @lc code=start
+class Solution:
+    def minAddToMakeValid(self, S: str) -> int:
+        left = right = 0
+        for i in S:
+            if right == 0 and i == ')':
+                left += 1
+            else:
+                right += 1 if i == '(' else -1
+        return left + right
+# @lc code=end
+